This invention relates to hydrogen generators and, more particularly, to a control system for hydrogen generators.
Hydrogen generators which produce quantities of relatively high purity hydrogen have several uses. The hydrogen produced can be fed to a hydrogen consuming device or it can be placed in a storage device which maintains it for future use. One type of consuming device is a fuel cell such as that used in a power generation system. The fuel cell is an electro-chemical device wherein the energy released in the oxidation of a fuel, such as hydrogen, is made directly available in the form of electric current. It is distinguished from a battery in that fuel is continuously or intermittently supplied to the cell and its electrodes are not consumed. During operation, it is necessary to feed hydrogen over one electrode of the cell to produce electric current.
A fuel cell system can be equipped with an integral hydrogen source to operate the cell over a period of time. Such a system can be designed to have the hydrogen produced by a hydrogen generator at the fuel cell site rather than having to rely on a hydrogen storage facility for its needs. This is desirable from the standpoint of safety. In addition, the hydrogen generator can be made demand responsive; that is, produce hydrogen only as needed by the fuel cell, thereby eliminating the need for any type of hydrogen storage facility.
In demand responsive hydrogen generators, there are several aspects of the hydrogen generation system which are important. It is desirable to precisely control the hydrogen formation process; that is, to start and stop the process substantially instantaneously. The generator desirably should not have a lag factor in providing hydrogen to the system that utilizes it. Otherwise, the continuous operation of the consuming device, such as a fuel cell, could be jeopardized. Similarly, the generator desirably should not have a lag factor in stopping the formation of hydrogen after the hydrogen requirements of the system have been satisfied. Any excess hydrogen would have to be bled from the system or placed in some sort of storage facility. Having to bleed off excess hydrogen would waste a portion of the hydrogen produced and make the generator somewhat inefficient.
There are other important considerations such as the rate of hydrogen production during the generator's operation. The formation of hydrogen must be at a sufficiently high rate for the application intended. The rate of hydrogen generation may be required to vary over time and, therefore, the control system should have the capability of being adjustable. The disablement of the generator from producing hydrogen should be complete when it is not intended to be in operation. It is also desirable that the control system be simple, inexpensive and reliable in construction.
It is a principal object of the invention to provide a hydrogen generator control system.
It is a further object of the invention to provide a hydrogen generator control system which automatically regulates the operation of the hydrogen generator in response to an output of a hydrogen consuming device.
It is a further object of the invention to provide a method of controlling the production of hydrogen.
It is a further object of the invention to provide a hydrogen generator control system which can be turned on and shut off substantially instantaneously.
It is a further object of the invention to provide a hydrogen generator control means which is adjustable as to the rate at which hydrogen is generated.